Print ribbon feed structure



United States Patent [72] inventor Harold F.Stlffler Scottsville, New York [21] AppLNo. 680,532

[22] Filed .Nov.6,1967

[45] Patented Nov. 24, 1970 [73] Assignee The Singer Company a corporation ofNew Jersey [54] PRINT RIBBON FiBED STRUCTURE 6 Claims, 5 Drawing Figs. 7

[52] U.S.Cl. 197/165 [51] 1nt.Cl. 1341133/44 [$0] FleldofSearch 197/l 5l,

[56] References Cited UNITED STATES PATENTS 917,803 4/1909 Scott 197/160 1,309,403 7/1919 Fort 197/160 1,937,145 11/1933 Gollwitzer.. 101/336 1,980,723 11/1934 Hartley.... l97/l6l 2,019,301 10/1935 Friden.... l97/l65UX 2,090,811 8/1937 Salmon... 197/165 2,902,136 9/1959 Whippo 197/165 3,037,448 6/1902 Blodgettetalm; 197/165X Primary Examiner- Ernest T. Wright, Jr. Attorneys-George W. Killian, Patrick J. Schlesinger, Charles R. Lepchinsky and Jay M. Cantor ABSTRACT: A print ribbon mechanism for advancing a ribbon from a supply reel to a takeup reel and then reversing the direction of travel of the ribbon just before the ribbon is exhausted from the supply reel so that the functions of the two reels are reversed. The takeup reelis driven by a coaxial ratchet wheel which is rotated in discrete increments by a reciprocating and pivotable driving member. The takeup ratchet is restrained from reverse motion by a retaining pawl which is coupled to the driving member. In response to the detection of the near exhaustion of the ribbon from the supply reel a drive reversing lever is pivoted and an interposer portion thereof is placed in a coacting relationship with the reciprocating and pivotable drive member to cause said last named member to pivot in response to the next reciprocating drive motion thereof. in response to the pivoting of the drive member. the drive pawl which had been driving the takeup ratchet wheel is disengaged therefrom and the ratchet wheel which had been associated with the supply reel is now engaged by a drive pawl and the last named wheel becomes the takeup wheel. The detent member pivots in response to the pivotal motion of the drive member thereby withdrawing the detent from the wheel associated with the former takeup reel and associating the detent with the new takeup wheel.

Inn]

INVENTOR HAROLD F. STIFFLER BY Q AGENT Patented Nov. 24, 1970 3,542,183

Shoot g m Pit" rfin tenrimnsrunerune' specifically, t'oa ribbonfeeding'and reversing ineflc'han sociatedfivitha print head cariierthat movesrela on laten r yp L 'niilafi-Tp intingmechanis'ms have been Know rsahdfityp'ically, they are provided with-a fabr ,ribb n'whjich is advanced-past the printing positio'n first in I thehthe other. The printin'g riband is wound on a 't'akeu'p' reel e: rib n on thesupply reel nears eitthe twoi'reels'a're interchanged and ta reel whilefthe'fakrup reel by movingthe ribbon in the speed serial char 'tfe nin a printin fat'arn h'hih ventioriril anuzi arid r'eifers'i" agepn'nie -Miih i nveiiitioiitofprovidea ribbonsa'da m ch hepresent inventionis illustrate, v de 165; id

g r f fish? ediiig and reversing iiation Ser -No. 630,904, filed not tlielfprese'nt ino he'ribbon'ifeeding and} li'efiribbonieeding and reversing.

interested in obtaining 'm'ore FIGS. 1-5 in thepresent application correspond to FIGS. 31,

stainedprintingrate than the con- 30, 34, 32, and 33, respectively, of the cited Blodgett application. For convenience, identical item numbers are used in the present applicationandthe cited Blodgett application.

The print head carrier includes a print, ribbon support and feed structure 545 by which'a print ribbon 544 is fed between ribbon supply and takeup reels 539 and passes across the end of the printing head nose block 189.'Thc structure 545 is fabricated upon a base plate 521 terminated at its ends in upstanding L-shaped arms having an arm portion 522 perpendicular to the base plate 521 and an arm portion 523 spaced from andfparallel to the base plate 521 and having a turned over edge providing a stiffening flange 523'. A tab 524 is struck out from the base plate 521' and machine screws 525 secure the arm portion 522 and tab 524 on the rear face of the carrier basecasting 150 below the nose block 189 of the print head as shownin FIGS. 1 and 4. As illustrated in detail in FIG.

1, an aperture 526-provided' in the end of each arm portion 523' arid-a coaitial aperture 527 provided inthe base plate 521 support individual ones'of two ribbon reel spindles 528 by means of a flanged bushing 529seated in the aperture 526 and a flanged bushing 530 seated in theaperture 527. A ratchet wheel 531 having ahub 532 is secured by a pin 533 on each ".spindle 528 and each spindle 528 is rotationally secured in place on the base plate 521 by spaced washers 534 with intervening compression springs 535'and a C-spring 536 seated in a peripheral groove 537provided in the end of each spindle 528 as shown. The upper end of-each spindle 528 is provided with a radial pin-538 which engagesthe slotted end 53% of thehub 539a of a ribbon reel 539 placed on the spindle 528'and thus drivingly couplesthe spindle528-and its associated reel 539.

A,V,-shaped bracket having a flat base portion541 and arms 540 with turned-over edges'to provide stiffening flanges 540',

1 has theends of its arms 5 jriveted by rivets 540a to the ends of individual ones of the arm portions 523 as shown more clearlyjn FIGS. lyand 2. Peripheral spaced edgeportions of the brack'etbase portion 54l'are turned up to provide plural spaced'pedestals 542.upon which split cylindrical sleeves 543 arev secured and, over which the print ribbon 5 44 passes inits travel from-one of the ribbon reels 539 to the other. The ribbon544nis guided around and past the end'of the print'head noseblock 189 by a unitarygguide structure 545 havinga configuration shown moreiclearly in FIG. 5; This guide structure 545 includes amounting base portion 546having an aperture 547 through whicha'jmachine screw 548passes to secure the guide structure 545 'on aprojecting boss 549 fabricated on the ---underside of thenoselblock l 89 as shown. The guide structure 545 has an upturned arm- 550 of T-coniiguration having tu'm'ed-baCk end portions 551'and turned-over edge tongues 55 2-spaced from thesu'rfa'ce ofthe arm 550 to guide the print 'ribbon 544'along the le'ng'thof the arm "550. The guide struc- 'turel545 includes a depending arm 553.having a tongue 554 struck therefrom and serving to deflect the edge of the paper, as it is being inserted on ,thegplaten 13 of the printer, pass the guide structure 545.

At' a giv-entime the print ribbon 544' isp'ulledby'the one of the reels 539 serving as-a driven takeup'reel from the other reel o'perating as a freely rotating supply reel 539. Compres- 'sio n'.;sp1';ing 535wprovidesa slight dragon the supply reel to maintaintensio'n in ribbQnQSMJI-E-ach time'the ribbon 544 on =theyprevailingsupply-reel 539 is ,nearing'exhaustion', the

direction of ribbon feed is automatically reversed in a manner Spresently to-be described andthe functions of the reels as 'takeu'pi and-"supplyreels539 are reversed. In considering the 'reel'drive arrangement, assume that the right-hand'ree'l 539as seen-in FIG. 12 is currently driven to operate ias the ribbon takeupyreel.fThe-drive"of the right-hand reel 539 isaccomu plished bystepped"rotational drive. of its associated spindle 52,8;To this end, thete'ethbftheassociated ratchetwheel S31 are'engag'edby the right-hand one of two end pawls 557' of a driveypawl member 558., The drive pawl member '558 is pivotally supportedon-a stud'559 carried bythe arm 560,'the

pawl niember558 being spaced from the arm'560 by a spacer bushing 561 (FIG. 4) carried by the stud 559 and extending through an aperture 562 (FIG. 2) of the base plate 521 formed by striking the tab 524 therefrom. One end of the arm 560 has an integral hub 563 (FIG; 1) by which it is pivotally supported on and in spaced relation to the base plate 521 by a base plate stud 564. The other end of the arm 560 extends between spaced guide bars 565, secured on the underside of the base plate 521, for guided motion over a range of reciprocal angular movements of the arm 560. Such reciprocal angular movement of the arm 560, accompanied by longitudinal reciprocation of the drive pawl member 558, is effected by the righthand one of the print head pressure plate actuating shafts 210 (as seen in FIGS. 1 and 2) as the latter reciprocates through a range of angular motion during each character print operation as more fully described in the cited copending Blodgett application. To this end, the shaft 210 carries an arm 566 having a stud 567 for pivotal connection to one end of a link member 568. The opposite end of this link member 568 is pivotally connected by a stud 569 to the arm 560 near its free end as shown and is spaced from the latter by a spacer bushing 570 (FIGS. 1 and 2).

The drive pawl member 558 is provided with a central end stud 571 which anchors one end of the overcenter spring 572 having its opposite end anchored by a stud 573 of arm 592. Slide member 574 has a pair of elongated slots 575 (FIG. 2) by which it is reciprocally secured by headed-rivets 576 on the base portion 541 of the V-shaped bracket having arms 540. Under the foregoing assumed conditions that the right-hand ribbon reel 539 in F102 is driven to operate as the takeup reel, the overcenter spring 572 biases the drive pawl member 558 clockwise (as seen in FIG. 2) about its pivot stud 559 to engage the right-hand pawl 557 with the teeth of the adjacent ratchet wheel 531. The reciprocal angular drive of the arm 560 and resultant reciprocal longitudinal drive of the drive pawl member 558 by the pressure plate actuating shaft 210 provides a one-tooth stepped rotational drive of the ratchet wheel 531 and reel 539. A pair of spaced detent members 577 are pivotally supported on and in spaced relation to the base plate 521 by base plate studs 578 and associated spacer bushings 579 (FIG. 4) and are mechanically connected by a link member 580 for concurrent pivotal motion on their pivot studs 578 and have free ends formed to provide detent pawls 581, and are connected by tension springs 582 to the drive pawl member 558 as shown. It will be evident that the positioning of the pawl member 558 to drive the right-hand ratchet wheel 531 as seen in FIG. 2 increases the tension of the left-hand spring 582 and thereby biases the right-hand detent pawl 581 into engagement with the teeth of the adjacent ratchet wheel 531 to maintain the latter stationary as the drive pawl 557 advances to engage the next succeeding tooth of the ratchet wheel 53]. During driven longitudinal reciprocal motion of the drive pawl member 558, the latter is confined for guided motion between the link member 580 and a guide bar 583 which is secured to the base plate 521 but is spaced therefrom by spacer bushings 584 as illustrated in FIG. 3.

During the assumed drive of the right-hand reel 539 in FIG. 2 as the takeup reel, the overcenter spring 572 biases the slide 574 to the left to a position at which the right-hand end of the slots 575 of the slide 574 engage the headed rivets 576. The slide 574 has integral U-shaped arms 589 positioned at its ends and through which the ribbon 544 passes. When the ribbon 544 on the left-hand supply reel 539 becomes nearly exhausted, an eyelet (not shown) provided on the ribbon 544 moves into engagement with the left-hand arm 589 of the slide 574 and continuing takeup pull exerted on the ribbon 544 by the right-hand takeup reel 539 causes the ribbon eyelet to move the slide 574 to the right against the bias of the overcenter spring 572. A drive reverse lever 59 is pivotally secured on the base plate 521 by a rivet 591 and has an upstanding arm 592 of U-shaped configuration (FIG. 4) and loosely coupled thereto for initiating the pivotal motion thereof is a depending stud 573 of the slide member 574. The opposite end of said drive reverse lever 590 terminates in an upstanding foot 593. As the slide member 574 is moved to the right as explained above, the depending stud 573 of the slide member 574 pivots the drive reverse lever 590 clockwise as seen in FIG. 2. Slot 573a in member 540 accommodates the motion of the depending arm 573. This pivotal motion of the lever 590 eventually positions its foot, or interposer member, 593 so that in response to the next longitudinal reciprocation drive motion of the pawl member 558 the interposer foot 593 is engaged by a step 594 provided on an enlarged O-shaped portion 595 of the pawl member 558 and causes the latter to pivot about pivot point 559 on the arm 560 and move the lefthand pawl 557 into engagement with the teeth of the left-hand ratchet wheel 53l. lt is biased into such engagement by the overcenter spring 572 which completes movement of the slide member 574 to the right where the left-hand end of its slot 575 engage the headed rivets 576. This pivotal motion of the pawl member 558 acting through the spring 582 disengages the detent pawl 581 of the right-hand detent member 577 from the teeth of the right-hand ratchet wheel 531. The ribbon feed is thereupon reversed; the left-hand ribbon reel 531 now operating as the takeup reel while the right-hand reel 539 operates as the supply reel. Upon near exhaustion of the supply ribbon 544 on the right-hand heel 539, an eyelet provided on the ribbon 544 engages the right-hand arm 589 of the slide member 574 and moves the latter to the left as seen in FIG. 2 with a consequent counterclockwise pivotal motion of the drive reverse lever 590 and eventual pivotal movements of the drive pawl member 558 and right-hand detent member 577 to effect driving engagements of the right-hand pawl 557 and detent pawl 58] with the right-hand ratchet wheel 531 thus again reversing the direction of the ribbon feed.

The print head assembly and the ribbon advancing and,

reversing structure are part of a subassembly having flanges 151 which allow motion of the subassembly on guide rail 153 all as more fully described in the cited copending Blodgett application.

While there has been shown and described what is considered at present to be the preferred embodiment of the invention, modifications thereto will readily occur to those skilled in the related arts. For example, modifications might be required in a type bar printer. It is believed that no further analysis or description is required and that the foregoing so fully reveals the gist of the present invention that those skilled in the applicable arts can adapt it to meet the exigencies of their specific requirements.

Iclaim: I

1. In a print ribbon feeding an reversing mechanism, first and second reels serving as ribbon supply and takeup reels, respectively:

a first ratchet wheel associated with said takeup reel for rotating said takeup reel in response to the rotation of said ratchet wheel;

guide means for guiding the ribbon from the reel serving as a supply reel, past a printing station and to the reel serving as a takeup reel;

drive means supported for reciprocating, pivotal and longitudinal motion within a plane parallel to the plane of said first ratchet wheel and having a first pawl portion for engaging said first ratchet wheel and rotating said first ratchet wheel in discrete increments in response to each cycle of longitudinal motion of said drive means;

a drive reverse lever pivotally supported at a point intermediate to its ends and adjustable to first and second stable positions;

detecting means coupled to one end of said drive reverse lever for pivoting said drive reverse lever from one stable position to the other in response to the imminent exhaustion of the ribbon from said ribbon supply reel;

said drive reverse lever having at its other end an interposer for engaging said drive means and providing a fulcrum about which said drive means is pivoted in response to the first longitudinal reciprocation of said drive means after the pivoting of said drive reverse lever and 2. The combination as set forth in claim 1 and including a second ratchet wheel, coplanar with said first ratchet wheel and which has thesame association with the supply reel that the said first ratchet wheel has with thesaid takeup reel, and wherein said pawl portion of said drive means is disengaged from said first ratchet wheel and another pawl portionlof said drive means engages said second ratchet wheel and rotates said second ratchet wheel indiscrete increments in response to each cycle of longitudinal reciprocation of said drive means after said drive means has been pivoted by said drive reverse lever, whereby the functions of said first and second reels have been reversed so that they become takeup and supply reels,

respectively.

3. The combination as set .forth in claim 2 and including individual detent means associated with each of said ratchet wheels, and coupling means for selectively engaging the appropriate one of said detent means with the ratchet wheel associated with the takeup reel. t

4. In a print ribbon feeding mechanism, firstand second reels each having as associated ratchet wheel for rotating their respective reels in response to the driven rotation of the ratchet wheel, said first and second reels serving alternately and selectively as takeup and supply reels for a ribbon supply:

detecting means for detecting when the ribbon supply on the supply one of said reels has neared exhaustion; a drive reverse lever pivotally mounted at a point intermediate to its ends for motion between first and second stable positions;

from one to the other of its stable positions each time said detecting means detects the near exhaustion of the ribbon supply on the supply reel; drive meansincluding a first pawl for engaging and driving the ratchet wheel associated with the takeup one of said reels; reciprocating means for cyclically reciprocating said drive means; said drive means being coupled to said reciprocating means by a pivot for. providing pivotal motion of said drive means relative to said reciprocating means; said drive reverse lever including at its other end an interposer extension .for engaging a portion of said drive means which is to one side of the longitudinal reciprocal line of motionof said drive means for causing a pivotal motion of said drive means in response to the first longitudinal motion of said drive means after the'pivotal motion of said'drive reverse lever; and unitary spring bias means coupled to said drive means and said drive reverse lever for urging said drive means and said drive reverse lever to pivot in opposite directions about their respective pivots. 5. The combination as set forth in claim 4 wherein a second pawl is included in said drive means for engaging the ratchet wheel associated with the reel, which had been the supply reel,

. subsequent to the pivotal motion of said drive means whereby coupling means coupling said detecting means and one end of said drive of ever for moving said drive reverse lever the reel, which had been the supply reel, becomes the takeup reel.

6. The combination as set forth in claim 4 and including detent means associated with the ratchet wheel associated with the takeup reel for preventing reverse rotation of the detented ratchet wheel.

22 8 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 542 183 Dated November 24, 1970 Inventor(s) Harold F. Stiffler It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

delete "an" and substitute therefor -and--;

delete and substitute therefor after "lever" add after "and" add said-- delete "supply:" and substitute therefor PP Y" delete "of ever" and substitute therefor --reverse lever Signed and sealed this 30th day of March 1 971 Column 4, line line line

Column 5, line line line (SEAL) Attest:

EDWARD M.FLE'I'GHER,JR.

Attesting Officer WILLIAM E. SCHUYLER, JR Commissioner of Patent: 

